Infectious Diseases

People experiencing homelessness are at an increased vulnerability of being exposed to and/or contracting various infectious diseases. This is because of difficulties related to their experiences of homelessness including: maintaining personal hygiene, obtaining adequate nutrition, staying in crowded and poorly ventilated environments, engaging in sex work, using intravenous (IV) drugs, and transitioning between imprisonment and homelessness.These factors make it more likely for some individuals, compared to the general population, to face problems with their immune systems.

Hepatitis

According to the World Health Organization (WHO), Hepatitis B is a viral disease that attacks the liver, whichcan cause both acute and chronic disease.The overall prevalence of acute and chronic Hepatitis decreased between the years 2005-2013 in Canada. Hepatitis B (acute) has reportedly gone from 1.0 to 0.5 per 100,000 people. There was also a decrease in the reported numbers of chronic Hepatitis B between 2009-2013, down from 13.6 to 12.0 per 100,000 people.

Among those who are experiencing homelessness, it is much more likely to contract Hepatitis B. One study found that 32.5% of individuals experiencing homelessness and using substances or facing mental health problems, tested positive for the Hepatitis B virus (HBV). As the vaccination for the prevention of Hepatitis B is administered in three doses, people experiencing homelessness often face barriers in completing their full dosage of treatment within the required 6-month period.

Hepatitis C, on the other hand, is a liver disease caused by the Hepatitis C virus.The virus can cause both acute and chronic hepatitis, ranging in severity from a mild illness lasting a few weeks to a serious, lifelong illness.

Overall, like Hepatitis B, there have been decreases in the reported incidences of Hepatitis C in the general population. For example, between 2005-2013, rates have dropped from 40.3 to 29.6 per 100,000 people in Canada.

However, those experiencing homelessness are still at an increased risk of infection. One study reported that among Torontonians experiencing homelessness, their risk of infection by the Hepatitis C virus was 29 times higher compared to the general population.

Even within the population of individuals experiencing homelessness, those who have Hepatitis C are more likely to experience adverse symptoms related to their infection such as regularly being in pain and in discomfort (61% versus 35%), or being “so tired [they] did not have the energy to walk one block or do light physical work” (72% versus 48%).

Tuberculosis (TB)

According to the World Health Organization (WHO), Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs. Tuberculosis is curable and preventable.

In Canada, the risk of contracting Tuberculosis is relatively low compared to other nations on a global scale. However, certain individuals have a higher risk of contracting TB, which is largely attributable to their living conditions and individual health circumstances.

People who previously used certain illegal drugs (through inhalation or injection)

Individuals with certain conditions or diseases such as HIV/AIDS

Those who have had TBin the past (but were unable to complete the full course of treatment)

In 2012, there were six reported cases of persons diagnosed with Tuberculosis, who were underhoused or experiencing homelessness in Toronto. Five were male and one was female. As of July 2013, one out of these six individuals had died of causes directly related to their Tuberculosis. One other person died due to their HIV-positive status, as AIDS had compromised their immune system. Furthermore, one person experienced success after treatment, whereas three others were still in the process of receiving treatment during the time of the Toronto Public Health report.

The World Health Organization (WHO) defines HIV as a virus that“targets the immune system and weakens people's defence systems against infections and some types of cancer. As the virus destroys and impairs the function of immune cells, infected individuals gradually become immune deficient.”

The most advanced stage of HIV infection is Acquired Immunodeficiency Syndrome (AIDS), which can take from 2 to 15 years to develop depending on the individual. AIDS is defined by the development of certain cancers, infections, or other severe clinical manifestations.”

In a Canadian context, certain groups of people are overrepresented in the HIV/AIDS statistics, including IndigenousPeoples, and individuals who have migrated from countries where HIV/AIDS is highlyprevalent. While the overall prevalence of HIV in Canada is low (0.2% in 2011), there are a number of sub-populations within Canada that aremost affected, including:

Gay men (or other men who have sex with men)

People who use injection drugs

People from countries with a high HIV prevalence rate

Indigenous Peoples

People in prison

Youth at risk

Women

Studies have found that one’s socioeconomic status and housing stability can have an impact on the treatment that individuals receive when living with HIV/AIDS. For example, individuals who experienced homelessnesswhile living with HIV/AIDS experienced more discrimination, compared to people who had a higher socioeconomic status (who encountered less discrimination).

60% of the families had to deal with income-loss after the HIV-diagnosis

31% had an income that was stable, but their expenses had increased

Future Directions

Although Canada is generally a nation that has relatively low prevalence rates for infectious diseases like Hepatitis, Tuberculosis and HIV/AIDS, it is also important to take into account the waysspecific populations, particularly those who are marginalized within society,are more vulnerable to becoming infected due to a variety of social factors. As well, it is also crucial to consider the associated stigmatization that occurs with certain diagnoses, and the barriers that different people face in terms of accessing adequate treatment.